Your only options would be a detent ring kit (I have two if you need one, rather than ordering). Or you could possibly treat it like the guys with the brass Sheridans do and use nail polish to build up a detent (but it helps if you normally use the same size or type of paint).

But this is the reason I went with my Freak kit and undercocking handle. Or I could have had my stock barrel bored out for Freak inserts.